Mostrando la salida de `cabal-plan` visualmente

Tue, 19 May 2026 13:01:49 +0200

Cuando corremos cabal plan diff hay mucho ruido en la salida. Este script de python muestra la salida mucho más accesible:

#!/usr/bin/env python3
"""Summarize the `Package versions` section of `cabal-plan diff` output.

Pipe `cabal-plan diff` (or similar) output to this script. It extracts the
section between the `Package versions` and `Dependency graph` headers, then
prints:

    pkg-name oldver -> newver        # for packages that changed
    new pkg-name ver                  # for packages only on the + side
    deleted pkg-name ver              # for packages only on the - side
"""

import re
import sys

LINE_RE = re.compile(r"^\s*([-+])(\S+?)-(\d[\w.]*)\s")


def parse(stream):
    in_section = False
    removed: dict[str, str] = {}
    added: dict[str, str] = {}

    for line in stream:
        stripped = line.strip()
        if stripped.startswith("Package versions"):
            in_section = True
            continue
        if stripped.startswith("Dependency graph"):
            break
        if not in_section:
            continue

        m = LINE_RE.match(line)
        if not m:
            continue
        sign, name, version = m.group(1), m.group(2), m.group(3)
        (removed if sign == "-" else added)[name] = version

    return removed, added


def main() -> int:
    removed, added = parse(sys.stdin)

    changed_names = sorted(set(removed) & set(added))
    only_removed = sorted(set(removed) - set(added))
    only_added = sorted(set(added) - set(removed))

    name_w = max(
        (len(n) for n in changed_names + only_added + only_removed),
        default=0,
    )
    old_w = max((len(removed[n]) for n in changed_names), default=0)

    for name in changed_names:
        print(f"{name:<{name_w}}  {removed[name]:<{old_w}} -> {added[name]}")

    if only_added:
        print()
        for name in only_added:
            print(f"new      {name:<{name_w}}  {added[name]}")

    if only_removed:
        print()
        for name in only_removed:
            print(f"deleted  {name:<{name_w}}  {removed[name]}")

    return 0


if __name__ == "__main__":
    sys.exit(main())

Se usa pasando la entrada en una tubería:

Classgraph

Thu, 15 Jan 2026 00:00:00 +0000

A GHC 9.14 type-checker plugin to create graphs of classes

Haskell on Javier Sagredo

Mostrando la salida de `cabal-plan` visualmente

Classgraph